Air flow control for jet propelled craft



July 19, 1960 R. HOFFMANN AIR FLow CONTROL FOR JET PROPELLED CRAFT 3Sheets-Sheet 1 Original Filed Aug. 2.

INVENTOR. 630/9 fil /o/f/hdlm G. R. HOFFMANN AIR mow CONTROL FOR JETPROPELLED CRAFT Original Filed Aug. 2, 1951 July 19, 1960 3 Sheets-Sheet2 INVENTOR. ea/ye 1Q Hoff/2mm? BY July 19, 1960 e. R. HOFFMANN AIR FLOWCONTROL FOR JET PRQPELLED CRAFT Original Fileql Aug. 2, 1951 3Sheets-Sheet 3 & i ll 1 tes AIR FLOW CONTROL FOR JET PROPELLED CRAFTGeorge R. Holfmann, 8145 Craig, Overland Park, Kans.

3 Claims. (Cl. 60- 35.6)

This invention relates to heavier than air equipment such as airplanes,missiles and the like, and more particularly to a thrust or jetpropelled engine, the primary object being to provide in combinationcertain novel features capable of reducing hazard, econornizing on fuelconsumption, and regulating the capacity thereof to suit the desires andneeds of the user.

This application is a division of my application, Serial No. 239,875,filed August 2, 1951, and now US. Patent 2,806,350.

It is the most important object of the present invention to provide athrust engine that includes a pair of telescoped tubes, both of whichare provided with a fairing to present the proper streamlining and eachbeing provided with, a separate air control, combustion chamber, fuelinjection system, means to ignite the combustible mixture, and structurefor eliminating the formation of ice at the air inlet of the tubes.

Another object of the present invention is the provision of a thrustengine wherein the air inlets of at least one of the aforesaid tubes isprovided with a plurality of vanes, movable toward and from a fullyclosed position whereby to control the air flow therethrough.

Another important object hereof is to provide a fuel injection systemfor thrust engines of the aforesaid character that includes means forpressurizing the raw liquid fuel prior to injection thereof into thecombustion chambers whereby a completely vaporized admixture ispresented to the engine and particularly to the air flow thereth'rough.

A further object hereof is to provide de-icing means as above indicatedand including a conductor in the form of a split ring that becomesenergized inmediately upon bridging of the ends thereof by water and/orice.

Another object hereof is to provide a fuel difiuser in one of theaforesaid tubes within the path of travel of the fuel injected thereintoand within the air stream through the tube for rotation thereby.

A further object of this invention is to provide air pressurizing meansadapted for secondary use as a fuel diffuser as aforesaid, including arotatable driven Wheellike device having a plurality of vanes that maybe tipped to control the extent of pressurizing and through the innertube.

Other objects include details of construction all of which will be madeclear or become apparent as the following specification progresses,reference being had to the accompanying drawing, wherein :2

Figure 1 is a fragmentary, vertical, cross-sectional view, partiallyschematic, showing a thrust engine made according to the presentinvention.

Fig.. 2 is a front end elevational view thereof.

. Fig; 3 is a cross-sectional view taken on irregular line III- 1H ofFig. 1.

Fig. 4 is a schematic wiring diagram of one of the de-.

icing assemblies.

Fig. Sis an elevational view, parts being broken away the air flow atentO to reveal the manner of assembling the engine into a missile or thelike.

Fig. 6 is a vertical, cross-sectional view through the inner tubeillustrating a modified form of diffuser adapted to pressurize airwithin the combustion chamber of the inner tube; and

Fig. 7 is a fragmentary, transverse, cross-sectional view taken onirregular line VII-VH of Fig. 6.

In Fig. 1 of the drawing there is illustrated a thrust engine of the jetpropelled type that includes an elongated, outermost tube 10 that issubstantially cylindrical throughout the length thereof, and an innertube 12 of appreciably smaller diameter and having an enlargedcombustion chamber 14, together with an elongated, cylindrical tail pipe16 integral therem'th.

The tubes 10 and 12 are preferably in coaxial relationship andinterconnected through the medium of suitable supporting struts 18 and20, both of which are preferably tubular and streamlined as indicated bydotted lines in cross-section by Fig. 1. An entrance-head 22 extendsoutwardly from the longitudinal axis of the tube 12 and is mounted on aninwardly extending shaft 24 that is in turn held in place by suitablestruts 26 within the tube -12.

The shaft 24 is additionally adapted to receive a shutter assemblybroadly designated by the numeral 28 and including a plurality of vanes30 extending radially relative to the shaft 24 and adapted to completelyclose the forwardmost end of the tube 12 when in the closed condition.Each vane 30 is provided with a pintle 32 pivotally carried by the tube12 adjacent the inlet end thereof and an opposed bevel pinion 34. All ofthe pinions 34 are in mesh with a pair of opposed bevel gears 36'and'38, carried by the shaft 24. Rotation of the gear 36 on the shaft 24controls the swinging movement of vanes 30 on their pintles 32 and gear38 freely rotatable on the shaft 24 serves as an idling stabilizer.annular gear 40 on the gear 36 receives a small pinion 42 that is inturn connected with a flexible cable 44 extending upwardly through thewalls of tube 12 and terminating exteriorly of the tube 10.

Fuel is supplied to the interiors of tubes 10 and 12 from a liquid fuelsupply tank 46 that is in turn connected with a second tank forming apressure chamber 48 by means of a line 50 having a check valve 52therein. A suitablecompressor 54 connected with the chamber 48 by a pipe56 is driven by a suitable prime mover such as an electric motor 58. Anoutlet line 60 for the pressure chamber 48 has a check valve 62 therein.Line 60 is in turn connected with a pair of conduits 66 and 68 for tubes10 and 12 respectively, and in turn provided with control valves 64 andrespectively.

The struts 18 carry a plurality of injection nozzles 70 directed towardthe outlet end of the tube 10 and connected with the conduit 60 by amanifold 72 surrounding the tube 12. Likewise, the-struts 26 have apluralit'y of fuel injection nozzles 74 directed into the combustionchamber 14 and connected with the conduit 68 by means of an annularmanifold 76 surrounding the shaft 24.

A diffuser 78 for the fuel emanating from nozzles 74 comprises anannular disc having a plurality of inclined, radial vanes 80 adaptingthe same for free rotation in response to the air flow through the tube12. The diffuser 78 is provided with a stub shaft 82 freely rotat- 5able within the innermost end of the shaft 24.

Fuel ignition means such as one or more spark plugs 84, is providedwithin the combustion chamber 14 of the pulse jet tube 12. Similarly,ignition means such ,as

0 flares 86 may be provided within the ram jet tube 10 on the strut 20if desired.

' Patented July 19, 1960 An internal,

assemblies 88 and 90 respectively at the air inlet ends thereofeach ofwhich comprises an annular strip 92- of conducting material providedwith spaced-apart ends 94 and 96 in the manner illustrated in Fig. 4ofthe drawingst --Ea'ch cannular strip-is mounted within suitableinsulating blocks 98 and each is connected witha 'source of electricalenergy such-as a battery 100 (Fig. 4

Whenthe thrust engine is used as a power means for a missile or rocket102-, as shown in Fig. '5 ofthedrawings, it is preferably housed withina streamlined' body 104; the entire enginebeing designated in Fig. ofthedrawings by the numeral 106. A war head 108 may be included as apart ofthe body 104 at one end of the latter andia tail assembly such as at 110may be provided at the opposite end of the body 104. The spaeing betweenthe engine 106 and the inner Walls of. the body 104 may be utilized toreceive a fuel tank, 112' and other necessary equipment such as radialcontrols, fuel pressurizing means and-the like, all broadly designatedby the numeral 114..

In operation, fuel is pressurized within the chamber 48 by means ofcompressor 54 prior to passage thereof tonozzles 70 and 74. as the casemay be. Control of the flow of pressurized fuel is obtained by suitableconnection within the cockpit (not shown) with the control valves 64 and65. The fuel emanating nfro m nozzle 74 is ,additional ly-vaporiz edbythe whirling diffuser 78 actuated, by the air-stream through the pulsejet tube 12. he irture here po n e y e Spark p gs. 84 th n. the mbus onc amber 14..

Similarly, the fuel emanating from the nozzles 70 is directed into. the.air-stream within tube 10, and surrounding tube 12 and; the admixture isignited by the ignition flares 86,

By means. of the. control cable 44 also leading to the cockpit, thevanes .28. may be opened or closed and held in any predeterminedposition as desired.

In the eventmoisture forms on the strips 92 of diffusers. .88 and 90,corresponding. electrical circuits will immediately be closed and theheat from the strips will prevent formation of ice. Inthis respect it isseen that the two de-icersoperate immediately to prevent collection ofice and therefore, reduce this hazard to a point where how of airthrough the pipes is at no time decreased by such ice collection.

It is apparent further that the shutter assembly 28- may be duplicatedaround the tube 12 and within tube and further, that such shutterassemblies may be rendered fully automatic in response to the velocityof air-flow through the tubes and/or under direct control of the pilotthrough flexible cables or the like as illustrated at 44; Since the fuelinjection means is separately controlled and such shutter means likewiseoperated selectively by the pilot, either or both of the tubes may beplaced in use.

In Figs. 6 and 7 of the drawings, there is illustrated a modifieddiffuser broadly designated by the numeral 116 that differs from thediffuser 78 in that the same is driven from an auxiliary source of powernot shown through a flexible cable 118 and is provided with a pluralityof blades 120 that are tiltab'le on their longitudinal axes. As in thecase of diffuser 78, a plurality of wheellike structures 116may beprovided if desired and while not shown in Figs. 6 and 7 of thedrawings, nozzle 74 may be disposed to, direct fuel into the combinationdiffuser and pressurizing structure 116.

An elongated shaft'122 is disposed on the longitudinal axis of an innertube 124 and extending inwardly. into combustion chamber 126 of tube124. A gearbox 123 surrounding the shaft 122 has a pair of gears 130 and132 thereon, gear 132 constituting a mere idler and shaft 122 beingfreely reciprocable and rotatable within the ait. 3.

Spiral groove 134 within the shaft 122 receives an car 136 forming apart of the gear 130. Each of the plurality of vanes is provided with apin 138 at the innermost end thereof for receiving a conical pinion 140disposed between the gears 130 and 132 in mesh therewith. Additionally,each vane 120 has a pintle 142 at the outermost end thereof freelyrotatable within an annular rim 144 in. turn; rota-table within aU-shaped track 146 on the inner face.- of: the tube 124.

A strut 148 within tube 124 has a semi-circular central portion 150 thatpartially surrounds the shaft 122 andparticularly an elongated gear 152thereon. Cable joins; with a small; gear 154. mounted on the strut 148and in mesh with the gear 152. A bracket 156. on the strut 148 pivotallyreceives a yoke 158 having an actuating rod 160 pivotally securedthereto. The yoke 158 embraces the shaft 122 within an annular groove162 formed therein,

The assembly 116 ismtated from the flexible cable 118- through gear 154,gears 152, shaft 122 ear 136, gear 130, pinions 140 and vanes 120 to rim144. In the event the pitch of the vanes 120 is, to be varied, eitherwhile the assembly 116" is rotating or in a stand-still condition, theshaft 122 is reciprocated on its longitudinal axis by actuation of rod160. Yoke 158 is thereby swung on the bracket 1,5,6 andsha ft 122, as,well as the gear 152, are shifted rectilinearly with respect to the gear154. Such movement of the shaft 152, rotates the gear 130 through thecar 136, thereby rotating all of the pinions 140 simultaneously andturning thev-anes 120. on their pintles 142.

It is obvious that if additional support is desired for the shaft 122,struts similar to strut 148 and including bearings for the shaft122, maybe provided on each side of the gear housing 128. Furthermore,cantilever sup:

port may be provided for the vanes 12 0 thereby eliminating the rim 144,pintles 142 and the track 146, It is clear that by driving the assembly116 faster than wouldbe possible through flow of air alone as in thecase of diffuser 78, the combustion chamber 126,is pressurized to suchdegree as may be desired through adjustment of the van& 120. Suchpressurizing of the combustion chamber increases the overall efficiencyof the engine and not only aids in supporting combustion, but provides apropulsion forcethat is considerably greater than made possible byreliance solely on the force of air through the inner tube. as: above.described in connection with the diffuser 78.

, It, is additionally noteworthy that while the impeller or supercharger116, hereof is shown for use in connection with a thrust engine, it isapplicable for use in, connection with various other types of air craftor prime movers generally where diffusing of fuel and/or pressurizing ofcombustion chambers or the like is desired.

' Having-thus described the invention what is claimed as new and desiredto be secured by Letters Patent is:

1. Jet propulsion. apparatus comprising an elongated, cylindricalinnertube; an elongated, cylindrical outer tube of substantially equaldiameter throughout the length thereof and surrounding said inner tubein spaced, co-' axial relationship thereto, said outer tube being ofstreamlined configuration, said tubes being of substantially equallength and having proximally disposed,- circular margins atcorresponding ends thereof defining respective air intakes, a rearportion of the. inner tube having a smaller diameter than the forwardportion thereof to present a cylindrical region of" greater transversecross-sectional area in surrounding relationship to said rear portion ofthe inner tube between thelatter and the opposed inner surface oftheoutertube, than the cross-sectional area of the annular regiondefined between said forward portion of the inner tube and the opposedinner surface of the outer tube, said front-portion of'the inner tubemerging smoothly with said rear portion thereof; adjustablei contromsaasw hi he air i t k bt n e tube for selectively varying the amount ofair permitted to pass thereinto during forward movement of saidapparatus; fuel and air diffuser means mounted within said forwardportion of the inner tube transversely thereof and in relatively closeproximity to said air intake of the same; a plurality of fuel injectorsmounted within the inner tube circumferentially thereof between said aircontrol means and the diffuser, and disposed to direct individual jetsof fuel under pressure directly against said diffuser means to therebyaspirate the same from said intake opening thereof to form a combustiblemixture within a zone of said forward portion of the inner tuberearwardly of said diifuser means; ignition means mounted on the innertube within said zone thereof and disposed in relatively close proximityto said diffuser means for igniting the combustible mixture within saidzone; a plurality of fuel injectors within the part of said outer tubesurrounding said forward portion of the inner tube, disposedcircumferentially around the inner tube and discharging rearwardly ofthe outer tube to aspirate air passing into the space between the innerand outer tubes to form a combustible mixture; and ignition means withinthe outer tube adjacent the outlet end of the inner tube for ignitingthe combustible mixture in said outer tube.

2. Jet propulsion apparatus as set forth in claim 1 wherein said aircontrol means within the air intake of said inner tube comprises a shaftmounted coaxial with said inner tube, a plurality of variable pitchshutter blades secured to said shaft in radially extending relationshipthereto, each of said shutter blades being rotatable about thelongitudinal axis thereof, gear means operably coupled with said shutterblades for varying the pitch thereof to and from closed positions, andactuating means connected to said gear means for permitting change inpitch of the shutter blades from a point remote from said outer tube.

3. Jet propulsion apparatus as set forth in claim 2 wherein saiddifiuser means comprises a disc rotatably mounted on said shaft incoaxial relationship thereto, said disc having a plurality of inclinedradial vanes of fixed pitch presenting slots of progressively increasingwidth as the outer ends of corresponding vanes are approached anddefining a turbine rotatable about said shaft under the influence of airand fuel therethrough, prior to ignition of said combustible mixture.

References Cited in the file of this patent UNITED STATES PATENTS2,474,068 Sammons et a1 June 21, 1949 2,508,288 Owner et a1 May 16, 19502,595,505 Bachle May 6, 1952 2,602,292 Buckland et al. July 8, 19522,610,465 Imbert et a1 Sept. 16, 1952 2,742,761 Mullen Apr. 24, 19562,773,350 Barrett et al. Dec. 11, 1956 FOREIGN PATENTS 627,885 GreatBritain Aug. 17, 1949

